Update to Drupal 8.2.6. For more information, see https://www.drupal.org/project/drupal/releases/8.2.6

vendor/symfony/console/Question/ChoiceQuestion.php

@@ -58,7 +58,7 @@ class ChoiceQuestion extends Question
      *
      * @param bool $multiselect
      *
-     * @return ChoiceQuestion The current instance
+     * @return $this
      */
     public function setMultiselect($multiselect)
     {
@@ -68,6 +68,16 @@ class ChoiceQuestion extends Question
         return $this;
     }
 
+    /**
+     * Returns whether the choices are multiselect.
+     *
+     * @return bool
+     */
+    public function isMultiselect()
+    {
+        return $this->multiselect;
+    }
+
     /**
      * Gets the prompt for choices.
      *
@@ -83,7 +93,7 @@ class ChoiceQuestion extends Question
      *
      * @param string $prompt
      *
-     * @return ChoiceQuestion The current instance
+     * @return $this
      */
     public function setPrompt($prompt)
     {
@@ -99,7 +109,7 @@ class ChoiceQuestion extends Question
      *
      * @param string $errorMessage
      *
-     * @return ChoiceQuestion The current instance
+     * @return $this
      */
     public function setErrorMessage($errorMessage)
     {